V 


THE  CATALYTIC  PREPARATION  OF  DIPHENYL  ETHER 
MIXED  DIALKYL  MERCURY  COMPOUNDS 

BY 

JOHN  BLACKWELL  DAVIS 
B.  S.  Beloit  College,  1920 


THESIS 

Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 

Degree  of 

MASTER  OF  SCIENCE 
IN  CHEMISTRY 

IN 

THE  GRADUATE  SCHOOL 

OF  THE 

UNIVERSITY  OF  ILLINOIS 
1922 


Digitized  by  the  Internet  Archive 
in  2016 


https://archive.org/details/catalyticpreparaOOdavi 


UNIVERSITY  OF  ILLINOIS 


THE  GRADUATE  SCHOOL 


January 16 _ \ 92  A 


I HEREBY  RECOMMEND  THAT  THE  THESIS  PREPARED  UNDER  MY 
SUPERVISION  BY_  _ John-B.  Davis 

ENTITLED The  Catalytic  Preparation  of  Diphenyl  Ether 

(a.ni ) Mixed  Dialkvl  Mercury  Compounds 

BE  ACCEPTED  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR 
THE  DEGREE  OF Master  of  Science 


In  Charge  of  Thesis 


Head  oi  Department 


Recommendation  concurred  in* 


Committee 


on 


Final  Examination* 


*Required  for  doctor’s  degree  but  not  for  master’s 


* 

■ 


ACKNOWLEDGMENT . 

The  writer  wishes  to  express  his  sincere  thanks 
and  appreciation  for  Dr.  Marvel’s  many  helpful 
suggestions  and  criticisms  received  in  the 
course  of  this  work. 


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TAELE  OF  CONTENTS. 

The  Catalytic  Preparation  of  Diphenyl  Ether, 

Introductory 

page  1 

Historical 

2 

Theoretical 

4 

Experimental 

l)  Elecrtic  Furnace 

6 

2)  Catalyst 

9 

3)  Effect  of  Aluminum  Oxide  on 

Phenol  at  High  Temperatures 

9 

4)  Effect  of  Aluminum  Sulfate  on 

Phenol  at  High  Temperatures 

11 

Summary 

13 

Mixed  Eialkvl  Mercury  Compounds. 

Introduction 

13 

Historical 

14 

Theoretical 

15 

Experimental 

l)  The  Preparation  of 

Benzyl  Mercury  Chloride 

17 

3)  The  Preparation  of 

Methyl  Mercury  Iodide 

18 

3)  reaction  of  Methyl  Magnesium  Iodide 

on  Benzyl  Mercury  Chloride 

19 

4)  Reaction  of  Ethyl  Magnesium  Bromide 

on  Methyl  Mercury  Iodide 

20 

Summary 

21 

I 


Part  I. 

The  Catalytic  Preparation  of  Diphenyl  Ether. 


-1- 


INTRODUCTORY. 

In  a recent  paper  by  A.  Maihle  and  F.  de  Gordon  1 on  the 
study  of  the  catalytic  preparation  of  ethers,  it  was  shown 
that  all  the  ethers  of  the  primary  aliphatic  alcohols-  up 
to  the  fifth  member  of  the  series-  could  be  prepared  by 
catalytic  methods.  These  workers,  using  a Jena  combustion 
tube  and  combustion  fmrnace, , obtained  pure  products  at 
fairly  low  temperatures  (200-230  degrees). 

Similar  methods  were  tried  by  Maihle  in  the  preparation  of 

3 

some  aromatic  ethers,  using  thorium  oxide  as  a catalyst  . 

3 

Likewise  mixed  ethers  have  been  prepared  catalytically  . 
Attempts  have  been  made  to  use  other  catalysts  such  as 
titanium  oxide  and  zirconium  oxide  in  the  preparation  of 
ethers  and  of  thiophenols,  none  of  which  was  as  satisfactory 
as  thorium  oxide. 

This  work  was  undertaken  in  an  attempt  to  develop  a cheap 

method  for  the  preparation  of  diphenyl  ether.  Aluminum  oxide 

was  chosen  as  a catalyst  since  it  is  known  that  aluminum 

phenolate,  upon  heating,  will  decompose  to  yield  diphenyl 
4 5 

ether.'  Also,  aluminum  oxide  is  very  cheap,  while  thorium 
oxide  is  comparatively  expensive.  An  electric  furnace  was 
used,  since  this  permitted  better  temperature  control. 

1.  Bui] . Soc.  chim.  25,565(1901)  27,131(1902) 

2.  Comp.  rend.  151,492(1910)  155, 261 (1913) 

3.  Comp.  rend.  155.  261(1912) 

4.  Ber.  15,  359TT6S3) 

5.  J.  Chem.  Soc.  41,8  (1882) 


V 


. 


HISTORICAL. 


Diphenyl  ether  has  been  prepared  by  the  use  of  a number 
of  chemical  reactions.  Hoffmeister  in  1871  first  prepared 
this  compound  by  the  condensation  of  benzene  diazonium  sulfate 
with  phenol.^  It  has  been  prepared  by  distilling  a mixture  of 
equal  molecular  amounts  of  sodium  phenolate  and  sodium 
metaphosphate;  by  the  condensation  of  potassium  phenolate 

rz  A 

and  brombenzene;  > by  the  use  of  flourbenzene  and  potassium 
5 

phenolate;  by  the  decomposition  of  the  ammonium  salt  of 

g 

phenyl  salicylic  acid;  by  the  distillation  of  aluminum 

7 

phenolate. 

A method  which  involves  the  dehydration  of  phenol  is  the 

action  of  three  parts  of  zinc  chloride  on  one  part  of  phenol, 

which  is  heated  in  a bomb  for  eight  hours  at  a temperature 

8 

of  350  degrees. J The  yield  in  this  case  was  only  5-6$  of 
the  weight  of  the  phenol.  None  of  the  above  methods  gave 
good  yields  and  in  almost  every  case  numerous  by-products 
were  obtained. 

Catalytic  methods  for  the  preparation  of  diphenyl  ether, 
as  well  as  numerous  other  aliphatic  and  aromatic  ethers,  have 
been  studied  quite  extensively  by  A.  Maihle. 


1.  Ann.  159,181  (1871) 


5.  Ann.  343,  230  (1888) 

6.  Ann.  257,  78  (1890) 


2.  Ber.  15,  1124  (1882) 

3.  Ber.  38,  2311  (1905) 

4.  Ann.  350,  85  (1906) 


7.  J.  Chem.Soc.  41,  8 (1882) 

8.  Ber.  14,  189  TT881) 


( 

-3- 

A catalytic  method  was  described  in  which  thorium  oxide 
was  used  as  a cata^st;1 2  titanium  oxide  and  zirconium  oxide 
were  both  tried  as  catalysts  by  these  workers,  but  the  best 
results  were  obtained  by  the  use  of  thorium  oxide. 

Aluminum  oxide  has  been  used  in  the  preparation  of  aliphatic 
ethers  but  no  record  was  found  of  its  having  been  used 
in  the  preparation  of  diphenyl  ether  nor  of  any  of  the  other 
aromatic  ethers. 


1.  Comp.  rend.  151 . 493  (1910) 

2.  Comp.  rend.  6,  329  (1920) 


. 


'* 


' 

. 


-4- 

THEORETICAL. 

Since  aluminum  oxide  has  been  successfully  used  for  the 
preparation  of  aliphatic  ethers,1 2 3 4 5  it  was  thought  that  it 
might  prove  a good  catalyst  in  the  preparation  of  the 
aromatic  ethers.  This  was  chosen,  also,  for  the  reason  that 
Gladstone  and  Tribe  obtained  a fair  percentage  of  diphenyl 

o 

ether  by  the  decomposition  of  aluminum  phenolate. J They 

heated  469  grs.  of  the  material  and  obtained  268  grs.  of 

distillate-  of  this  amount,  over  60 $ was  found  to  be  diphenyl 

ether.  Likewise,  Maihle  and  F.de  Gordon  obtained,  by  the  use 

of  aluminum  oxide  as  a catalyst,  diethyl  ether  in  as  high 
. 3 

as  71  $ yields.  Dipropyl  ether  was  prepared  by  the  same  workers 
with  yields  up  to  54$.  The  preparation  of  certain  mixed  ali- 

4 

phatic  ethers  is  also  described  in  the  literature,  which 

compounds  the  author  claims  have  been  prepared  heretofor  only 

by  "purely  chemical"  methods. 

The  theory  of  the  mechanism  of  the  dehydration  action  is 

described  as  being  analagous  to  the  action  of  sulfuric  acid 

on  primary  alcohols.0 

Ohf  -t-  > /-/*  O + ^ H 

-S  C v H < C /,  -h  Ch  M-zh+i  (d*  O + i 

^ A/  C-Ai  y-/  ♦ C A,  "t  d)  dy.  ff  ^ 

Thus  the  sulfuric  acid  is  regenerated  at  the  temperature 
necessary  for  the  formation  of  the  ether. 

1.  Coup.  rend.  170,  329  (1920) 

2.  J.  Chem.  Soc.  j41,  8 (1882) 

3.  Bull.  soc.  chim.  25,  565  (1901);  27,  121  (1902) 

4.  Bull.  soc.  chim.  27.  328  (1902) 

5.  Comp.  rend.  150,  823  (1910) 


. 


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-5- 


Similar  reactions  are  supposed  to  take  place  when  such  a 
catalyst  as  thorium  oxide  is  used.  The  thorate  and  water  is 
first  formed  by  the  action  of  the  phenol  on  the  oxide  and 
the  thorate  in  turn  decomposed  into  the  ether  and  the  original 
oxide.1  r 

z(c*  -OH)  y Z5  4,  —*  77,  o (oCh  Hzh+i)z  + HiO 
77,  o (ocr,  y Zh-OH  --*•  2 (r<-  O C7  y 7f,o(o/t)^ 

71  o C °R)x  » 77,  + 74  a.  O 

Titanium  oxide  and  zirconium  oxide  behave  similarly.  The 

theory  of  the  mechanism  in  the  preparation  of  diphenyl  ether 

by  the  use  of  thorium  oxide  as  a catalyst  was  similarly 
3 

described.  , v f \ 

£ fcb  //s  oHj  + 7J>0*  + 7 ?ofo  - 6^ 

7Z  O (oCo  > Th  + (it 

In  working  with  aluminum  oxide  it  was  expected  that  a 

similar  reaction  might  take  place. 

6 ((tZ/rw;  * v3/4  o +-  z (Z£(ou  //0J3 

2 aJ,  (ocb  Hs)  3 * t ^3^-3  fa  fa)*.  ° 

This  method,  however,  was  not  found  useful  because  at  the 
temperature  required  for  the  formation  of  diphenyl  ether,  a 
secondary  reaction  occurs  and  the  diphenyl  ether  is  converted 
into  diphenylene  oxide  and  hydrogen. 


\ 


V 


o 


> 


/ 


c 


o 


H: 


1.  Comp  rend.  151 . 359  (1910) 
3.  Comp  rend.  151,  493  (1910) 


* 


- 


. 


-6 


EXPERIMENTAL. 

Electric  Furnace. 

A piece  of  ordinary  one  inch  iron  pipe  was  cut  to  a length 
of  (Potty  inches.  One  end,  at  "A”,  was  fitted  with  a pipe  "T" 
and  about  eight  inchee  of  pipe  fitted  into  this  at  right  angles 
to  the  long  pipe.  The  opposite  end,  at  "B",  was  filed  smooth 
and  a condenser  later  fitted  on.  The  pipe  was  covered  with  a 
layer  of  alundum  cement  about  one-quarter  of  an  inch  in 
thickness,  extending  from  the  "T"  to  within  an  inch  or  two  of 
the  opposite  end.  The  cement  was  allowed  to  dry  thoroughly 
and  then  forty  or  fifty  feet  of  #14  chromel  "C"  resistance 
wife  was  wound  on  this  layer.  Care  was  taken  to  have  the  coils 
of  wire  so  placed  as  not  to  make  contact;  also,  although  the 
wire  was  wound  tightly,  it  must  not  be  wound  tight  enough  to 
cut  through  the  cement  layer  and  thereby  make  contact  with 
the  metal.  The  coil  was  tied  to  the  pipe  firmly,  leaving 
enough  wire  at  both  ends  to  make  connections.  Over  this  coil 
was  plastered  another  layer  of  cement,  of  sufficient  thick- 
ness to  completely  cover  the  wire.  This  layer  was  allowed  to 
dry  for  about  twenty-four  hours  and  then  thoroughly  baked  on 
by  passing  a current  through  the  wire  for  an  hour  or  so. 

After  this  treatment,  there  resulted  a hard,  firm  cement 
layer  and  the  pipe  could  be  handled  readily  without  danger  of 
the  cement  falling  off. 

The  bottoms  were  removed  from  five  or  six  ordinary  tin 
cans  and  these  then  fitted  together  so  as  to  form  a jacket, 
the  length  of  which  could  be  regulated.  Holes  were  cut  in 


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jf 


the  center  of  two  of  the  covers-  just  large  enough  to  fit  over 
the  pipe  and  cement  layer,  these  to  serve  as  ends  for  the 
jacket.  Two  smaller  holes  were  punched  in  one  of  the  covers  to 
hold  small  porcelain  tubes,  an  inch  or  two  long-  made  from 
broken  porcelain  triangles,  to  serve  as  insulators  for  the  ends 
of  the  heating  coil  which  are  to  be  terminated  outside  of  the 
jacket  on  suitable  binding  posts.  This  cover  was  fitted  down 
over  the  pipe  and  cement  layer  to  the  pipe  "T"  at  "A"  and 
securely  fastened  there.  Both  ends  of  the  nichrome  wire  were 
cleaned  and  spliced  to  separate  pieces  of  #16  copper  wire. 

The  piece  of  copper  wire  at  "A"  need  only  be  about  sixteen 
inches  long.  The  piece  spliced  to  the  resistance  wire  at  "3" 
should  be  long  enough  to  reach  back  to  "Art.  This  length  is 
conducted  back  to  "A”  through  a piece  of  capillary  glass 
tubing,  out  through  the  porcelain  insulator  and  fastened  to 
a suitable  binding  post.  The  binding  posts  were  bolted  to  a 
strip  of  wood  which  was  wired  to  the  upright  piece  of  pipe. 

The  shorter  piece  of  copper  wire  was  conducted  out  through  the 
other  insulator  and  fastened  to  the  other  binding  post.  The 
copper  wire  is  more  convenient  to  use  on  the  outside  of  the 
jacket,  since  it  does  not  heat  up  to  any  degree  while  the 
furnace  is  in  operation.  Care  was  taken  to  so  bend  those 
parts  of  the  wires  which  were  to  be  enclosed  in  the  jacket, 
so  that  they  would  not  make  contact  upon  a slight  jarring  of 
the  apparatus. 

The  jacket  was  slipped  down  over  the  pipe  and  fitted  snugly 
to  the  cover  at  "A".  This  jacket  was  then  filled  with  a 
quantity  of  "Sil-Q-Cel"  as  a heat  insulator  and  the  cover 


. 

. 


-8- 

plaoed  on  at  MB '* . The  open  end  of  the  pipe  "T"  waa  fitted  with 
a one  by  ^tree-quarter  inch  bushing,  carrying  a well  of 
sufficient  length  to  extend  about  half  way  into  the  furnace, 
and  sealed  at  that  end.  This  smaller  pipe  was  used  to  hold  the 
pyrometer  or  thermometer.  The  jacket  surrounding  the  furnace 
was  covered  with  one  thickness  of  ordinary  steam-pipe  covering 
and  this  fastened  in  place  with  metal  bands. 

When  the  furnace  was  wound  for  the  first  time,  two  coils 
of  about  #17  wire  were  used;  arranged  so  that  one  was  wound 
between  the  coils  of  the  other.  It  was  hoped  that  this 
arrangment  might  afford  better  temperature  control,  since  one 
might  pass  current  through  one  or  both  coils.  In  actual  use, 
however,  the  furnace  burned  out  twice  with  this  arrangment  - 
probably  due  to  the  fact  that  the  coils  were  necessarily  wound 
too  close  together,  since  about  sixty  feet  of  wire  was  used. 
About  three  feet  of  13  mm.  glass  tubing  was  fastened  to  the 
pipe  at  ”3”  to  serve  as  an  air  condenser. 


, 


■ 


‘ 

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* 


-C>_ 

<y 

Catalyst. 

Sufficient  pumice  was  ground  to  about  pea  size  to  fill 
the  furnace  to  within  an  inch  or  two  of  the  end.  This  was 
thoroughly  soaked  in  water  for  1-3  hours  and  then,  while  moist, 
rolled  in  10-15  gr3.  of  powdered  aluminum  oxide  (c.p.  ) until 
the  pieces  were  well  coated  with  the  catalyst.  Ths  furnace  was 
then  filled  to  within  a few  inches  of  the  end,  with  this 
material.  The  smaller  pieces  were  dropped  in  first  so  as  to 
have  that  part  surrounding  the"well "filled  with  the  material. 

In  one  or  two  runs,  aluminum  sulfate  was  used  as  a catalyst. 
Ths  proceedure  in  this  case  was  to  boil  the  finely  divided 
pumice  with  a saturated  solution  of  aluminum  sulfate  for  about 
one  hour.  It  was  then  allowed  to  dry  and  used  as  in  the  case 
of  the  oxide. 

-The  Effect  of  Aluminum  Oxide  on  Phenol  at  High  Temperatures. 

In  the  first  run  the  temperature  of  the  furnace  was 
190-300  degrees.  lOOgrs.  of  phenol  was  weighed  into  an 
ordinary  distilling  flask  and  distilled  into  the  furnace  thru 
the  upright  iron  pipe.  In  this  and  the  next  two  or  three  runs, 
a dark  brown  liquid  distilled  over  - the  color  of  which  was 
probably  due  to  the  reduction  o£  a quantity  of  rust  in  the 
pipe  and  the  formation  of  oxidation  products  of  phenol.  Dense 
white  fumes  accompanied  the  liquid,  which  condensed  only  upon 
standing  for  an  hour  or  so.  The  liquid  distillate  was  shaken 
with  strong  NaOH  solution.  The  entire  distillate  was  soluble, 
and  when  again  acidified  and  distilled,  pure  crystals  of  phenol 
were  obtained,  leaving  a small  amount  of  a black  tarry  substance 


. 

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■ 


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-10- 


in  the  distilling  flask.  About  35  minutes  were  required  in  this 
run  for  the  distillation  of  the  phenol  into  the  furnace. 

A second  run  was  made,  again  using  100  grs.  of  phenol  and 
distilling  it  into  the  furnace  at  a temperature  of  190-200  deg. 
The  time  required  for  distillation,  however,  was  about  1^  hours. 
The  distillate  was  again  shaken  with  strong  sodium  hydroxide 
solution,  acidified  and  the  phenol  recovered.  The  entire  amount 
of  distillate  was  soluble  in  the  alkali  and  an  amount  of 
tar  was  again  left  upon  recovery  of  the  phenol. 

Two  other  runs  were  made  at  this  temperature,  but  with  a 
lengthening  of  the  time  required  to  distill  the  phenol  into 
the  furnace.  The  longest  time  required  was  2g  hours.  In  each 
case  practically  all  of  the  phenol  was  recovered,  unchanged. 

The  furnace  was  then  filled  with  a new  supply  of  the  catalyst. 
This  time,  however,  the  pumice  was  boiled  for  1-2  hours  with 
a thin  paste  of  the  aluminum  oxide,  then  allowed  to  dry.  This 
was  done  in  hopes  that  the  pores  of  the  carrier  might  become 
impregnated  with  the  catalyst,  and  the  catalytic  action  thus 
be  increased.  The  time  required  for  this  run  was  S-Sj  hours. 

Six  subsequent  runs  were  made  at  the  following  temperatures : - 
200-210°;  240-260°;  280-300°;  330-350°;  365-375°;  400-425? 

In  no  case,  however,  was  any  product  other  than  phenol  obtained. 

Another  method  was  tried-  using  100  grs.  of  phenol  and  at 
a temperature  of  460-490°.  This  consisted  in  inserting  the 
end  of  the  air  condenser  into  a stopper  and  fitting  this  into 
a vacuum  filter  flask.  Also,  the  pumice  was  packed  into  the 
furnaae  more  tightly  and  a slight  suction  applied  during  the 


run. 


. 


. 

. 


11- 


In  this  way  the  rate  of  distillation  of  the  phenol  could  be 
easily  controlled.  Three  runs  were  made  requiring  about  three 
hours  each.  In  one  case,  upon  the  addition  of  the  strong  alkaline 
solution  to  the  distillate,  there  separated  out  a small  quantify 
of  a brown  precipitate*  This  was  filtered  off  and  a melting 
point  taken.  It  melted  at  30-33°; and  burned  leaving  a black 
residue.  A.  Maihle  describes  the  formation  of  diphenylene  oxide 
by  the  action  of  thorium  oxide  on  phenol  at  475?  which 
compound  melted  at  83?  This  therefore,  was  concluded  to  be 
diphenylene  oxide-  although  there  was  only  enough  formed  to 
take  a melting  point.  The  other  two  runs  yielded  only  alkali 
soluble  material  and  phenol  was  recovered  from  this  in  each 
case. 

The  action  of  aluminum  sulfate  pJienol  .high,  .hemps ratnre.3. 

Two  runs  were  made  using  aluminum  sulfate  as  a catalyst. 

100  grs.  of  phenol  was  distilled  into  the  furnace  at  510-530° 
in  three  hours,  a slight  suction  also  being  used.  The  products 
in  both  cases  were  alkali  soluble  and  phenol  was  recovered. 

Two  runs  were  made  using  a dropping  funnel.  The  phenol  was 
dissolved  in  a small  amount  of  benzene  and  dropped  into  the 
furnace  slowly-  instead  of  distilling  it  in.  The  temperature  in 
this  case  was  450-460°  and  the  time  of  the  run  was  about  ij  hrs. 
This  method  of  introducing  the  phenol  was  not  very  satisfactory, 
since  the  speed  with  which  the  mixture  was  introduced  into 
the  furnace  could  not  be  so  readily  controlled.  The  products 
were  alkali  soluble  in  both  cases. 

When  working  with  temperatures  below  350°  a thermometer 


-12- 

was  used.  In  all  cases  where  the  temperature  was  above  350°,  a 
pyrometer  was  made  use  of. 


SUMMARY. 

Several  attempts  have  been  made  to  prepare  diphenyl  ether 
catalytically,  in  an  electric  furnace,  using  aluminum  oxide  and 
aluminum  sulfate  as  catalysts.  Temperatures  varying  from 
200°to  500°  have  been  used.  In  no  case  wa3  any  diphenyl  ether 
obtained.  At  490°,  aluminum  oxide  converts  some  phenol  into 
diphenylene  oxide.  This  seems  to  indicate  that  the  catalytic 
formation  of  diphenyl  ether  is  not  possible-  using  aluminum  oxide 
as  a catalyst-  since  it  decomposes  into  diphenylene  oxide  with 
a loss  of  hydrogen  at  any  temperature  high  enough  to  cause  the 
dehydration  of  the  phenol. 


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Part  IT 


Mixed  Dialkyl  Mercury  Compounds. 


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INTRO  DUC  TORY. 

In  a recent  article,  Jones  and  Werner  described  some  work 
on  aromatic  mercury  compounds,1  from  which  they  formulated  a 
theory  concerning  the  electronic  structure  of  dialkyl  and  di- 
aryl mercury  compounds.  Their  assumption  is  that  one  of  the 
valences  functions  positively  and  the  other  negatively.  Thus, 
according  to  this,  we  may  have  compounds  of  the  type:- 

— ~j< 

t * 

— + _ + f 

K — *3  — * 

This  work  was  undertaken  in  an  attempt  to  prepare  some  mixed 
dialkyl  mercury  compounds,  keeping  in  mind  the  possibility  of 
the  utilization  6f  these  as  a proof  of  the  types  of  valence 
on  mercury  in  organic  compounds. 


1.  J.  Am.  Chem.  Soc . 40,  1257  (1918) 


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HISTORTCAL. 

Hilpert  and  Gruttner,in  1915,  described  the  preparation  of 

a number  of  dialkyl  mercury  compounds  and,  among  them,  benzyl 

ethyl  mercury,  which  is  the  first  mixed  dialkyl  mercury 

1 m 

compound  to  be  described.  This  compound  was  prepared  from:- 
C_  ^ Hs  /&r-  -4-  cp  C.  //j  OJL  - — > < p c //*_  //  j C »-  Ms  fj 

In  the  same  paper,  the  following  mixed  alkyl-aryl  compounds 

were  described:-  benzyl  mercury  phenyl,  benzyl  mercury  ethyl, 

ethyl  mercury  phenyl  and  benzyl  mercury  o-tolyl. 

A number  of  simple  diaryl  and  dialkyl  mercury  compounds 

have  been  prepared.  Duppa  and  Frankland  describe  the  preparation 

2 

of  mercury  diethyl  and  mercury  dimethyl.  Wolff  has  prepared 

3 

diphenyl  mercury;  Pope  and  Gibson  describe  the  preparation  of 

4 

dibenzyl  mercury.  However  with  the  exception  of  the  work  of 
Hilpert  and  Gruttner,  very  little  is  known  concerning  the 
mixed  organic  mercury  compounds. 


1.  Ber.  48,  906  (1915) 

3.  Ann.  130,  105  (1865) 

3.  Ber.  48,  64  (1915) 

4.  J.  Chem.  Soc.  101,  735  (1912) 


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THEORETICAL. 

If  mercury  in  organic  compounds  really  has  one  positive 
and  one  negative  valence,  a compound  such  as  benzyl  mercury 
methyl,  upon  treatment  with  hydrochloric  acid,  should  hydrolyze 
in  two  different  ways:- 

(V  G&s-  Q & *■  CM* 

t l 

fij  CiHsC-Z/t — C/J3  ' ^ ' * V ^ 3C 

In  studying  the  reaction  of  the  Grignard  reagent  on 

mercuric  chloride,  it  hat  been  found  that  one  of  the  atoms 

of  chlorine  is  much  mors  easily  replaced  by  an  alkyl  group 

than  is  the  second  atom,-"  It  was  thought  that,  by  making  use 

of  this  fact  and  preparing  mixed  dialkyl  mercury  compounds 

step-wise,  the  electronic  isomers  in  this  series  might  possibly 

be  obtained.  Thus,  benzyl  methyl  mercury  prepared  in  the 

following  way  might  exist  in  two  isomeric  forms. 

0)  <p  /y^  CJZ  v-  OP-  //j  » <&>  c /-/j  CJ2  •*- 

Hj  at  -*•  c//_3  sgjS  —+  5^°^  c//y  + 

(zj  C/6^  S + cs-Mj-e*  c //3  /£}  ^ 

C//3  MyS  + cj?  <?>  ^ 

If  the  products  obtained  from  these  two  series  of  reactions 
break  down  differently  upon  treatment  with  hydrochloric  acid, 
or,  if  the  products  behave  in  the  same  way,  but  still  give  all 
of  the  decomposition  products  mentioned  above  ( a,b),  then  the 
evidence  furnished  by  these  experiments  would  favor  the  theory 
of  Jones  and  We*ner. 

1.  Marvel  and  Gould-  J.  Am.  Chem.  Soc . January  1933. 


: 


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However,  if  the  products  obtained,  from  the  above  reactions 
behave  in  the  same  way  toward  acids  and  yield  only  one  set 
of  deconiposi tion  products,  the  evidence  would  not  be  so 
favorable  to  this  theory. 

After  this  work  had  been  started,  there  appeared  a paper 
by  Kharasch  and  Jacobsohn,'1'  in  which  the  theory  of  Jones  and 
Werner  was  more  or  less  conclusively  disproved. 

Due  to  the  extremely  harmful  physiological  action  of  these 
mercury  compounds,  it  was  found  necessary  to  discontinue  the 
work  on  this  problem,  before  any  conclusive  results  were 
obtained. 


. Am.  Chem.  Soc,  _43,  1894  (1931) 


1.  J 


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EXPERIMENTAL. 

Benzyl  Mercury  chloride. 

a) Preparat ion  of  the  Grignard  reagent . 

In  a 500cc  round  bottom  flask,  fitted  with  a rdflux 
condenser,  is  placed  a mixture  of  8 gre.  of  magnesium  turnings 
and  200  cc  of  anhydrous  ether.  A separatory  funnel  is  used  to 
add,  thru  the  condenser,  40  grs.  of  benzyl  chloride-  a crystal 
of  iodine  is  also  added,  as  a catalyst.  Upon  the  addition  of  a 
few  drops  of  the  benzyl  chloride  and  slight  heating  for  a few 
minutes,  the  reaction  begins  and  runs  smoothly.  The  benzyl 
chloride  is  dropped  in  just  fast  enough  to  kepp  the  reaction 
going.  The  mixture  is  refluxed  for  about  an  hour,  after  the 
addition  of  the  benzyl  chloride.  Any  unchanged  magnesium  is 
removed  by  rapid  filtration  thru  glass  wool. 

b)  Reaction  of  the  Grignard  with  mercuric  chloride . 

In  a three-necked,  three  liter  round  bottom  flask, 
fitted  with  a condenser  and  a mercury-seal  stirrer,  is  placed 
a mixture  of  80  grs.  of  dry, powdered  mercuric  chloride  and 
200  cc  of  dry  ether.  It  was  found  advisable  to  add  the  mercuric 
chloride  to  the  ether  with  continual  stirring,  so  that  it  would 
not  settle  and  form  a cake  at  the  bottom  of  the  flask.  The 
Grignard  prepared  above  was  added  to  this  mixture,  drop  by  drop, 
with  continual  stirring.  The  reaction  mixture  heats  up  during 
the  addition  of  the  Grignard,  which  may  be  added  just  rapid 
enough  to  keep  the  ether  refluxing  gently.  After  all  the 
Grignard  has  been  added,  the  mixture  is  refluxed  0$  the  steam-bath 
for  45  minutes.  The  flask  is  then  cooled  and  100-150  cc  of 
water  added,  to  decpmpose  any  excess  Grignard  reagent. 


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The  mass  is  then  filtered  with  suction,  washed  with  water  and 
a little  dilute  hydrochloric  acid,  sucked  dry  and  recrystallized 
from  boiling  alcohol,  separating  in  3hiny  leaflets-m.p.  104° 

The  mother  liquors  from  the  filtration  were  concentrated,  the 
precipitate  filtered  off  and  treated  as  above.  In  all,  55  grs., 
67$  of  the  theory  were  obtained. 

Notes:-  Two  runs  were  made  in  which  the  ether  was  distilled 
off  from  the  final  reaction  mixture  before  any  water 
was  added.  In  both  cases  the  yield  was  very  small, 
seemingly  due  to  a decomposition  of  the  product 
during  the  distillation  of  the  ether.  It  was  found 
that  prolonged  refluxing  after  the  addition  of  the 
Grignard  reagent  did  not  increase  the  yields;  but 
the  use  of  freshly  prepared  benzyl  chloride,  in 
making  the  Grignard  was  found  to  be  advantageous. 

Methyl  Mercury  Iodide 

a)  Prep  ration  of  the  Grigna rd  pe agent. 

In  a 500  cc  round  bottom  flask,  fitted  with  a reflux 
condenser,  is  placed  a mixture  of  18  grs.  of  magnesium  turnings 
and  300  cc  of  dry  ether-a  crystal  of  iodine  is  added  as  a catalyst 
Thru  the  condenser,  by  means  of  a separatory  funnel,  73  grs. 
of  methyl  iodide  are  gradually  added.  After  the  addition  of  a 
small  amount  of  the  methyl  iodide  and  alight  heating,  the 
reaction  runs  smoothly  and  is  finally  completed  by  refluxing 
for  about  an  hour.  Any  unchanged  magnesium  l£  filtered  off 
rapidly  through  glass  wool. 

b)  Reaction  of  the  Grignard.  with  mercuric  chloride. 

In  a three-necked,  three  liter  round  bottom  flask. 


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fitted  with  a reflux  condenser  and  a mercury-oeal  stirrer,  is 

placed  a mixture  of  140  grs.  of  mercuric  chloride  and  400  cc 

of  anhydrous  ether-  observing  .the  same  precautions  as  in  the 

preparation  of  benzyl  chloride.  The  Grignard  reagent  was  slowly 

added  to  this  mixture,  with  continual  stirring  and  after  all  of 

it  had  been  added,  the  reaction  mixture  refluxed  for  about  an 

taour.  The  flask  was  then  cooled,  and  a small  quantity  of  water 

added  (35-30  00)".  The  ether  was  distilled  off  and  the  residue 

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shaken  with  a mixture  of  300  cc  of  water  and  5 - 10  cc  of 
hydrochloric  acid.  The  mass  wa.s  then  filtered,  washed  and  sucked 
dry  on  the  Buchner  funnel.  The  product  contained  an  amount  of 
mercuric  iodide  and  two  crystallizations  from  hot  alcohol  were 
necessary.  The  mother  liquors  yielded  more  product  upon  concen- 
tration. The  crystals  were  slightly  yellow  in  color  and  melted 
at  143-143?  The  yield  was  73 $ of  the  theory. 

Notes:-  The  presence  of  a trace  of  mercuric  iodide  causes  a 
slight  red  coloration;  even  upon  recrystallization 
the  product  seems  to  decompose  upon  standing  with 
the  -formation  of  an  unknown  red  decomposition  product. 

Reaction  of  methyl  magnesium  iodide  on  benzyl  mercury  chloride. 

a)  Preparation  of  tfoe  Grignard  Reagent . 

This  was  prepared  in  the  usual  way  from  3j  grs.  of 
magnesium  turnings;  15  grs.  of  methyl  iodide  and  150  cc  of  dry 
either  and  the  reaction  mixture  filtered  rapidly  thru  glass  wool. 

b ) reaction  of  the  Grignard  with  benzyl  mercury  chloride . 

In  a 500  cc  round  bottom  flask  fitten  with  a reflux 
condenser,  was  placed  100  cc  of  dry  ether  and  29  grs.  of  benzyl 
mercury  chloride.  To  this  mixture,  the  Grignard  was  slowly  added. 


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The  reaction  mixture  was  refluxed  for  12  hours.  At  the  ehd  of 
that  time  there  was  left  a small  amount  of  a white  solid  whifah 
was  entirely  insoluble  in  the  ether.  Upon  addition  of  water  to 
the  solution  there  separated  out  a white  crystalline  substance, 
which  melted  over  a range  of  four  degrees-  from  72°-76? 

Elementary  analysis  showed  both  iodine  and  chlorine  to  be 
present.  It  was  probably  a mixture  of  benzyl  chloride  and  iodide 
and  methyl  chloride  and  iodide. 

Notes:-  Upon  the  addition  of  the  Grignard  reagent  to  the 

ether  solution,  a vigorous  reaction  took  place  which 
necessitated  the  cooling  of  the  flask  with  ice. 

Reac tioi  of  Ethyl  Magnesium  Bromide  .on  Methyl  Mercury  Iodide 

a)  Preparation  of  the  Grignard  Reagent . 

The  reagent  was  prepared  from  4 grs.  of  magnesium  and 
10.6  cc  of  ethyl  bromide  in  160  cc  of  dry  ether,  filtering  the 
product  thru  glass  wool  to  remove  any  unchanged  magnesium. 

b)  Reaction  of  the  Grignard  with  methyl  mercury  iodide. 

In  a 500  cc  round  bottom  flask  fitted  with  a reflux 
condenser,  was  placed  a mixture  of  43  grs.  of  methyl  mercuric 
iodide  and  150  cc  of  anhydrous  ether.  The  Grignard  was  added 
slowly,  through  the  condenser.  There  resulted  a vigorous  reaction 
which  necessitated  the  cooling  of  the  mixture,  during  the 
addition  of  the  Grignard.  It  was  then  refluxed  for  three  hours 
and  allowed  to  stand  over  night.  A small  amount  of  insoluble 
material  was  left.  10-20  cc  of  water  was  added  to  the  reaction 
product  and  the  layers  separated.  The  solid  in  the  ethereal 
layer  was  filtered  off  and  the  filtrate  distilled.  A very  small 


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quantity  of  solid  was  left  in  the  distillation  flask,  and  at  no 
time  did  the  temperature  rise  above  36? 

The  solid  was  dried  and  an  elementary  analysis  showed  bromine 
and  iodine  to  be  present.  It  melted  £rom  151°-  154°  and  was 
probably  a mixture  of  ethyl  mercuric  bromide  and  methyl  mercuric 
iodide . 

No  attempts  were  made  to  further  identify  the  compounds 
resulting  from  these  condensations-  beacuse  of  the  physiological 
action  of  them. 


SUMARY. 

The  Grignard  reagent  has  been  used  in  the  preparation  of 
alkyl  mercury  halides.  However,  the  reaction  between  an  alkyl 
mercury  halide  and  the  Grignard  does  not  seem  to  run  smoothly 
to  gtve  mixed  mercury  dialkyl  compounds. 


